A Saudi Arabia health worker who traveled to Orlando, Fla., has tested positive for the deadly MERS coronavirus, the second case ever confirmed within the United States, health officials said Monday.

Officials with the U.S. Centers for Disease Control and Prevention told reporters at a news conference that health officials were notifying more than 500 people who may have come in contact with the patient during a series of plane flights this month.

Though there is no vaccine for the virus, and death has resulted in 27% of documented cases, CDC officials said the disease did not appear to be highly contagious.

Notification of exposed airline passengers was being conducted out of an "abundance of caution," they said.

"Our experience with MERS so far suggests that the risk to the general public is extremely low," said Dr. Tom Frieden, director of the CDC. "Transmission requires close contact -- for example, caring for someone when they're sick at home or sick in the hospital."

The most recent case does not appear to be linked to an earlier case in Indiana, said Dr. Anne Schuchat, director of the CDC's National Center for Immunization and Respiratory Diseases. (That case also involved a healthcare worker who had traveled to the U.S. from Saudi Arabia.)

MERS, which stands for Middle East respiratory syndrome, first appeared in 2012. Although it is believed to have originated in camels, its exact origin remains a mystery.

To date, health authorities in the Middle East and Europe have documented 538 lab-confirmed cases, 145 of which have resulted in death. Roughly 20% of the confirmed illnesses have involved healthcare workers.

Schuchat said the patient in the most recent case was traveling from Saudi Arabia to visit relatives in Orlando and began to experience fever, chills and a slight cough during a May 1 flight from Jidda to London.

The patient continued to feel unwell on subsequent flights to Boston, Atlanta and Orlando, officials said. After continuing to feel ill, the healthcare worker went to a hospital emergency room May 8 and was admitted.

"The patient is isolated in the hospital, and is doing well," Frieden said.

The male patient was admitted to Orlando's Dr. P. Phillips Hospital, according to the CDC and a statement from the Florida Department of Health.

"We are taking every precaution but believe the risk of transmission from this patient is very low since his symptoms were mild and he was not coughing when he arrived at the hospital," the hospital's infectious disease officer, Dr. Antonio Crespo, said in a statement.

CDC and Florida health officials would not release the patient's age, citing patient privacy laws. However, a number of media outlets, including Reuters, reported that he was 44.

To date, the median age for infection has been 49, with slightly more males contracting the illness than females, according to the World Health Organization.

The Florida Department of Health statement also said the patient was admitted May 9, not May 8, as reported by the CDC.

The symptoms of MERS coronavirus are similar to flu and include congestion, cough, fever over 100.4 degrees Fahrenheit, shortness of breath, pneumonia, body aches and diarrhea, according to health officials.

As a reminder, health officials said that people can protect themselves from communicable diseases by washing their hands often with soap and water, or an alcohol-based hand sanitizer if soap and water aren't available.

They said people should also avoid touching their eyes, nose and mouth with their hands, and that they should stay home when they are sick.

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